Employee salaries and items coding

i have two questions the first is about the ability of registring the name of the employee with every sale invoice to collect information about each employees sales.
the second question is about items and why the name of the item doesnt show in the sales invoice but the invoice shows the code only

To Track employee Sales try using Tracking codes.
Give the “code” a name you want to display or give description that will display on invoice with the Code you set.